Wever will play a young graduate student, Karlene Faith, who was sent in to prison to teach the women after the death penalty was lifted and they were given life sentences.

It is due to begin filming in Los Angeles in the spring and will be penned by Harron’s American Psycho writing partner Guinevere Turner based on source material from The Family by Ed Sanders, as well as The Long Prison Journey of Leslie Van Houten, written by Faith.

Smith played the Duke Of Edinburgh for two series of The Crown but is due to be replaced for the third.

It has already been announced that Olivia Colman will take over from Claire Foy as the Queen, and Helena Bonham Carter is tipped to replace Vanessa Kirby as Princess Margaret.

Another film about Charles Manson, directed by Quentin Tarantino, is also in the works, with Leonardo DiCaprio reported to star as an ageing actor.